So what do you make of a rock album that begins with “Ode to Isis,” an orchestral slow build that chants the names of mythological gods? Or the lecture-prone title track, the 5⁄4 meters, or even the pictures of Bach and Shakespeare inside? Are Austin’s . . . AND YOU WILL KNOW US BY THE TRAIL OF DEAD , who have always worn their loaded name with a knowing smirk, finally living up to their pretentious moniker? Fear not. On their fourth (and second major-label) release, WORLDS APART (Interscope), Trail of Dead haven’t moved from punk to prog rock. Surrounding the overblown ambition is a gale force of sonic melody. Songs like “Caterwaul” and “Let It Dive” layer on guitars, drums, and keyboards until they find a ferocious kind of beauty.